The invention relates to a stack consisting of a multiplicity of bags which are connected to one another and are made of plastic film, in particular vending machine bags, having a filling opening and a flap which is on one side and has stack openings and at least one initial cutting point.
In continuous production of bags, it is generally known to gather together in a collecting apparatus a specified number of bags to form so-called bag stacks. A suitable collecting apparatus is, for example, a stud-type stack conveying device having a stud-type stack conveyor chain which moves in the horizontal direction and receives the severed bags on stacking studs. The stack openings, whose distance apart corresponds to the distances between the stacking studs on the stud-type stack conveyor chain, are punched into each bag. During the production of the bag stacks it is furthermore known to fix said stacks by means of a wicket, specifically in such a manner that the limbs of the wicket are guided through the stack openings in the flap part of the bags. For this purpose, either the bag stacks are lifted off the stacking studs of the stud-type stack conveying device and placed with the bags, which now rest loosely on one another, onto the limbs of the wicket, or the limbs of the wicket are inserted into the hollow groove-like recesses in the stacking studs of the stud-type stacking conveyor chain and the particular bag stack is removed in this manner.
In order to stabilize the bag stacks and to protect them against being damaged by the ends of the wickets as a plurality of bag stacks are being packaged together, the bag stacks are laid between a front and rear cover sheet and are additionally secured by securing washers or rubber stoppers placed on the limbs of the wickets. All of these procedures are generally carried out manually by an operator.
Apart from the considerable outlay on auxiliary materials, it can be quite difficult to package and transport bag stacks of this type because of the unwieldy wickets.
Considerable disadvantages also arise during the packing procedure, i.e. when filling a bag with a product, for example with a loaf of bread or the like. During the filling procedure, the wicket, which is inserted through the punched-out stack openings, serves to fasten the bag stacks in the packaging machine, for example an automatic packaging machine. Since during the packing procedure the inserted product, for example a loaf of bread, is drawn off together with the bag surrounding it, it follows that the filled bag is conveyed linearly to a sealing device. The linear drawing off of the bag with the inserted product not only requires a bag which is precisely formed in terms of dimensions, but since there is a sudden initial tearing of the initial cutting point, which is conventionally located between the stack openings and the front edge of the flap, a frayed appearance results. The xe2x80x9cfrayedxe2x80x9d edge region of the flap not only makes the bag look unsightly, but the flap surface is no longer readily suitable for securely attaching sealing elements, such as sticky labels or the like, and/or as a surface to print on or hold information.
Finally, after all of the bags are filled, the wickets have, if appropriate, to be transported back again to the manufacturer, i.e. to the producer of the bags, sorted according to size and, if appropriate, processed so that they can be reused.
The object of the invention is to provide a bag stack of the type mentioned at the beginning which can be handled, in particular packed and filled, substantially more simply, and, moreover, is distinguished by having an attractive exterior.
Another object is to provide a process by means of which interconnected bags, in particular vending machine bags, can be produced in a simple manner, with a good appearance in the edge region, and can be filled conveniently and neatly.
Furthermore, it is an object to provide an apparatus for producing and filling interconnected bags without complex auxiliary aids.
This object is achieved with regard to the product by the initial cutting point being formed as a tear-off perforation by perforation lines which in each case run at an angle with respect to the filling opening and delimit a corner section, and by at least one interconnecting point interconnecting the bags in the stack being arranged in each corner section.
A stack formed in such a way can be produced in a simple manner, conveniently transported and just as easily filled. The wickets which have hitherto been required can be completely dispensed with. It is possible, in particular, to organize the product and further handling of the bags substantially more cost-effectively, since the costs and, if appropriate the transporting of the wickets to and from between the packer and the manufacturer are omitted. It is merely necessary in the packing region to separate the topmost bag in each case rapidly and reliably from the bag stack and in so doing to hold the bag in such an opening position that the product (loaf of bread) can be inserted in a trouble-free manner into the bag. In the case of a filling procedure to be handled in accordance with the process according to the invention, this can be achieved by, in order to fill the topmost bag in each case of the bag stack, holding the bag at least in the region of its filling opening and/or of the flap, in such an opening position that the perforation between the corner sections and the flap is inevitably at least partially torn open and the bag is thereby at least partially detached from the interconnection in the stack.
Preferably the tearing open of the perforation takes place before the product to be packaged is inserted into the bag. This enables an exact tearing off along the perforation lines to be ensured in a simple manner.
The tearing open of the perforation by means of the opening procedure can be exactly regulated, namely by the configuration of the perforation lines, in particular their angular position and/or strength and/or their continuous or shortened extent between the side wall and the front edge of the flap, and the opening procedure during the filling of a bag being coordinated with each other.
Furthermore, this manner of proceeding makes it possible for the opening procedure to cause the perforation between the secured corner sections and the flap to be torn open, and also to cause the bag, which is detached from the bag stack, to be held in the opening position. In this manner, two functions are solved by one procedure, namely firstly the tearing open of the perforation, and secondly the securing of the bag during the packaging procedure.
If the aim is to obtain exact tearing off, particular attention has to be paid, among other things, also to the securing and interconnecting of the bags and of the bag stack. A particularly favorable solution is produced if the interconnections provided in the corner sections are designed as interconnecting holes, and the bag stack is suspended and/or held via these interconnected suspension opening during filling of the bags.
When the bag stack is suspended in this way, it is possible, in principle, to dispense with particularly large punched holes as suspension openings, as have hitherto been necessary for the wickets, in the remaining flap. However, in order to be able to collect the bags in a collecting device during the production process, the stack openings are either produced by pin holes, or else cross recesses are punched into the flap in order to form the stack openings.
With regard to the apparatus, the holding of the opened bag and the tearing off therefore from the bag stack in the filling station can be achieved in a particularly simple manner if an expanding device can be moved into a tear-off position effecting the only and at least partial severing of the tear-off perforation of the bag to be filled. The tear-off position can preferably correspond to the opening position which is necessary in order to insert a product or a loaf of bread. In contrast to the previous functions of an expanding apparatus, which merely had the task of forming the bag opening approximately corresponding to the shape and dimensions of the product to be packaged, the current expending device has two additional functions, namely firstly to secure the bag during the packaging procedure, and secondly to undertake the opening movement in such a manner that the expanding elements cause the perforation to be broken open completely or virtually completely.
Finally, the holding of the bag stack in a packer is assisted by a clamping plate provided below the plane of movement of the expanding elements of the expanding device, and an adapter used which has holding rods, at a distance from the interconnecting holes of the bag stack, and, with the interconnection of a transverse bracket, has fastening rods whose distance apart and diameter correspond to the dimensions of the limbs of a conventional wicket or receiving spikes of the packaging machine. The use of this adapter has the substantial advantage that the conventional packaging machine or automatic packaging machine, as was previously used for the insertion of wickets, hardly needs to be changed, if at all.
In addition, the use of an adapter gives the option of designing the lengths of the holding rods in such a manner that a plurality of comparatively large bag stacks can be stacked one above another, so that there is overall a noticeable increase in productivity during packing.